Add setuptools-scm support for dynamic version (#31)

* setuptools-scm added

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Author: davidsanfal

README.md

@@ -76,7 +76,8 @@ Configure in `pyproject.toml` under `[tool.conan-py-build]`:
 
 | Option | Description | Default |
 |--------|-------------|---------|
-| `version-file` | Path to a Python file from which to read `__version__` when `[project].version` is dynamic | (none) |
+| `version.file` | Path to a Python file containing `__version__ = "x.y.z"` (see [Dynamic version](#dynamic-version)) | (none) |
+| `version.provider` | Set to `"setuptools_scm"` to resolve version from git tags (see [Dynamic version](#dynamic-version)). Mutually exclusive with `version.file`. | (none) |
 | `conanfile-path` | Path to the Conan recipe (directory containing `conanfile.py` or path to the file), relative to project root | `"."` (project root) |
 | `wheel.packages` | List of paths (relative to project root) of Python packages to include in the wheel; each must be a directory with `__init__.py` | `["src/<normalized_project_name>"]` |
 | `sdist.include` | List of paths or patterns to add to the sdist | `[]` |
@@ -85,10 +86,26 @@ Configure in `pyproject.toml` under `[tool.conan-py-build]`:
 
 ### Dynamic version
 
-There is limited support for dynamic version: set `dynamic = ["version"]` in
-`[project]` (no `version` key) and point to a Python file via
-`[tool.conan-py-build].version-file` (e.g. `"src/mypackage/__init__.py"`). The
-backend reads `__version__ = "x.y.z"` from that file.
+Set `dynamic = ["version"]` in `[project]` (no `version` key) and configure the version source in `[tool.conan-py-build.version]`:
+
+**From a file** — reads `__version__ = "x.y.z"` from a Python file:
+
+```toml
+[tool.conan-py-build.version]
+file = "src/mypackage/__init__.py"
+```
+
+**From git tags (setuptools-scm)** — resolves version from VCS tags (e.g. `v1.0.0` → `1.0.0`):
+
+```toml
+[tool.conan-py-build.version]
+provider = "setuptools_scm"
+```
+
+The `setuptools-scm` options are configured in `[tool.setuptools_scm]` — see the
+[setuptools-scm docs](https://setuptools-scm.readthedocs.io/) for available options.
+
+> **Note:** `version.file` and `provider = "setuptools_scm"` are mutually exclusive.
 
 ### License files (PEP 639)
 

examples/basic-pybind11/pyproject.toml

@@ -10,8 +10,8 @@ license = "MIT"
 license-files = ["LICENSE"]
 requires-python = ">=3.8"
 
-[tool.conan-py-build]
-version-file = "python/myadder_pybind11/__init__.py"
+[tool.conan-py-build.version]
+file = "python/myadder_pybind11/__init__.py"
 
 [tool.conan-py-build.wheel]
 packages = ["python/myadder_pybind11", "src/extra_utils"]

pyproject.toml

@@ -39,6 +39,7 @@ dependencies = [
 dev = [
     "pytest",
     "build",
+    "setuptools-scm",
 ]
 
 [project.urls]

src/conan_py_build/build.py

@@ -118,33 +118,88 @@ def _resolve_conanfile_path(conanfile_path: str, source_dir: Path) -> Path:
     return Path(full_path)
 
 
-def _get_version_from_config(source_dir: Path) -> Optional[str]:
-    """Read version from [tool.conan-py-build] version-file if set. Reads pyproject from source_dir."""
-    tool = _get_tool_config(source_dir)
-    version_file = tool.get("version-file")
+def _validate_version_config(source_dir: Path) -> None:
+    """Validate [tool.conan-py-build.version] settings."""
+    version_cfg = _get_tool_config(source_dir).get("version", {})
+    provider = version_cfg.get("provider")
+    has_file = bool(version_cfg.get("file"))
+
+    if provider is not None and provider != "setuptools_scm":
+        raise RuntimeError(
+            f"[tool.conan-py-build.version].provider must be 'setuptools_scm', "
+            f"got {provider!r}. To read version from a file, use version.file instead."
+        )
+
+    if has_file and provider:
+        raise RuntimeError(
+            "[tool.conan-py-build.version].file and provider = 'setuptools_scm' "
+            "are mutually exclusive. Use one or the other."
+        )
+
+    if not has_file and not provider:
+        raise RuntimeError(
+            "[tool.conan-py-build.version] must define 'file' or 'provider'."
+        )
+
+
+def _uses_setuptools_scm(source_dir: Path) -> bool:
+    """True when [tool.conan-py-build.version].provider is 'setuptools_scm'."""
+    return _get_tool_config(source_dir).get("version", {}).get("provider") == "setuptools_scm"
+
+
+def _get_version_from_file(source_dir: Path) -> Optional[str]:
+    """Read __version__ from the path in [tool.conan-py-build.version].file."""
+    version_file = _get_tool_config(source_dir).get("version", {}).get("file")
     if not version_file:
         return None
     resolved = (source_dir / version_file).resolve()
     try:
         resolved.relative_to(source_dir.resolve())
     except ValueError:
         raise RuntimeError(
-            f"version-file must be inside project: {version_file!r}"
+            f"[tool.conan-py-build.version].file must be inside project: {version_file!r}"
         )
     return _read_version_from_file(resolved)
 
 
+def _get_version_from_scm(source_dir: Path) -> str:
+    """Get version from setuptools-scm."""
+    try:
+        from setuptools_scm import Configuration, _get_version
+    except ImportError:
+        raise RuntimeError(
+            "setuptools-scm is required when provider = 'setuptools_scm'. "
+            "Add 'setuptools-scm' to [build-system].requires."
+        )
+
+    config = Configuration.from_file(str(source_dir / "pyproject.toml"))
+    try:
+        version = _get_version(config, force_write_version_files=True)
+    except TypeError:
+        version = _get_version(config)
+    if version is None:
+        raise LookupError(
+            "setuptools-scm could not detect a version. "
+            "Build from a git repo with tags, or from an sdist."
+        )
+    return version
+
+
 def _resolve_version(project_metadata: dict, source_dir: Path) -> str:
     version = project_metadata.get("version")
     dynamic = project_metadata.get("dynamic")
     version_is_dynamic = isinstance(dynamic, list) and "version" in dynamic
 
-    if not version:
-        version = _get_version_from_config(source_dir)
-        if version_is_dynamic and not version:
+    if not version and version_is_dynamic:
+        _validate_version_config(source_dir)
+        if _uses_setuptools_scm(source_dir):
+            version = _get_version_from_scm(source_dir)
+        else:
+            version = _get_version_from_file(source_dir)
+        if not version:
             raise RuntimeError(
                 "dynamic = [\"version\"] but version could not be resolved. "
-                "Set [tool.conan-py-build] version-file to a file with __version__ = \"x.y.z\" at module level."
+                "Set [tool.conan-py-build.version].file or provider = 'setuptools_scm'."
             )
 
     version = version or "0.0.0"
@@ -275,14 +330,17 @@ def _create_dist_info(staging_dir: Path, metadata: dict, project_dir: Path) -> P
 
 # PEP 517 Hooks
 
-
 def get_requires_for_build_wheel(config_settings: Optional[dict] = None) -> list:
     """PEP 517 hook: Return additional dependencies needed to build a wheel."""
+    if _uses_setuptools_scm(Path.cwd()):
+        return ["setuptools-scm"]
     return []
 
 
 def get_requires_for_build_sdist(config_settings: Optional[dict] = None) -> list:
     """PEP 517 hook: Return additional dependencies needed to build an sdist."""
+    if _uses_setuptools_scm(Path.cwd()):
+        return ["setuptools-scm"]
     return []
 
 
@@ -546,6 +604,11 @@ def build_sdist(sdist_directory: str, config_settings: Optional[dict] = None) ->
     resolved_conanfile = _resolve_conanfile_path(conanfile_path, source_dir)
     default_include.append(resolved_conanfile.relative_to(source_dir).as_posix())
 
+    if _uses_setuptools_scm(source_dir):
+        version_file = _read_pyproject(source_dir).get("tool", {}).get("setuptools_scm", {}).get("version_file")
+        if version_file:
+            default_include.append(version_file)
+
     default_exclude = [
         "__pycache__",
         "*.pyc",

tests/test_integration.py

@@ -1,4 +1,6 @@
 """Integration tests: run real PEP 517 hooks (build_sdist, build_wheel) on a project layout."""
+import os
+import subprocess
 import tarfile
 import types
 import zipfile
@@ -9,10 +11,8 @@
 from conan_py_build.build import build_sdist, build_wheel
 
 
-def make_integration_project(path: Path) -> None:
-    """Create a minimal conan-py-build project"""
-
-    (path / "pyproject.toml").write_text("""[project]
+_DEFAULT_PYPROJECT = """\
+[project]
 name = "integration-pkg"
 version = "0.1.0"
 description = "For integration tests"
@@ -21,11 +21,10 @@ def make_integration_project(path: Path) -> None:
 [build-system]
 requires = ["conan-py-build"]
 build-backend = "conan_py_build.build"
-""", encoding="utf-8")
-
-    (path / "LICENSE").write_text("MIT", encoding="utf-8")
+"""
 
-    (path / "conanfile.py").write_text("""from conan import ConanFile
+_DEFAULT_CONANFILE = """\
+from conan import ConanFile
 from conan.tools.cmake import cmake_layout
 
 
@@ -43,15 +42,30 @@ def source(self):
 
     def build(self):
         pass
-""", encoding="utf-8")
-
-    (path / "CMakeLists.txt").write_text("""cmake_minimum_required(VERSION 3.15)
-project(integration_pkg)
-""", encoding="utf-8")
-
-    (path / "src" / "integration_pkg" / "__init__.py").parent.mkdir(parents=True)
-
-    (path / "src" / "integration_pkg" / "__init__.py").write_text("", encoding="utf-8")
+"""
+
+
+def make_integration_project(
+    path: Path,
+    *,
+    pyproject_toml: str = _DEFAULT_PYPROJECT,
+    conanfile: str = _DEFAULT_CONANFILE,
+    pkg_name: str = "integration_pkg",
+    init_content: str = "",
+    license_text: str = "MIT",
+) -> None:
+    """Create a minimal conan-py-build project."""
+    path.mkdir(exist_ok=True)
+    (path / "pyproject.toml").write_text(pyproject_toml, encoding="utf-8")
+    (path / "conanfile.py").write_text(conanfile, encoding="utf-8")
+    (path / "CMakeLists.txt").write_text(
+        "cmake_minimum_required(VERSION 3.15)\nproject(x)\n", encoding="utf-8"
+    )
+    if license_text:
+        (path / "LICENSE").write_text(license_text, encoding="utf-8")
+    pkg = path / "src" / pkg_name
+    pkg.mkdir(parents=True, exist_ok=True)
+    (pkg / "__init__.py").write_text(init_content, encoding="utf-8")
 
 
 @pytest.fixture
@@ -149,3 +163,78 @@ def test_build_wheel_with_profile_autodetect(integration_project, monkeypatch):
     assert profile_path.is_file(), "conan-py-build.profile should be created when autodetect is set"
     content = profile_path.read_text()
     assert "[settings]" in content or "os=" in content, "Profile should contain Conan settings"
+
+
+def _git_init_and_tag(cwd, tag):
+    """Initialise a throw-away git repo, commit everything and create *tag*."""
+    env = {
+        **os.environ,
+        "GIT_AUTHOR_NAME": "test",
+        "GIT_AUTHOR_EMAIL": "t@t",
+        "GIT_COMMITTER_NAME": "test",
+        "GIT_COMMITTER_EMAIL": "t@t",
+    }
+    for cmd in (
+        ["git", "init"],
+        ["git", "add", "."],
+        ["git", "commit", "-m", "init"],
+        ["git", "tag", tag],
+    ):
+        subprocess.run(cmd, cwd=cwd, check=True, env=env, capture_output=True)
+
+
+def test_build_sdist_version_file(tmp_path, monkeypatch):
+    """Integration: build_sdist resolves dynamic version from [tool.conan-py-build.version].file."""
+    proj = tmp_path / "proj"
+    make_integration_project(proj, pkg_name="file_pkg", pyproject_toml="""\
+[project]
+name = "file-pkg"
+dynamic = ["version"]
+description = "Test"
+
+[build-system]
+requires = ["conan-py-build"]
+build-backend = "conan_py_build.build"
+
+[tool.conan-py-build.version]
+file = "src/file_pkg/__init__.py"
+""", init_content='__version__ = "2.3.4"')
+    monkeypatch.chdir(proj)
+    monkeypatch.setenv("CONAN_HOME", str(tmp_path / "conan_home"))
+
+    sdist_dir = tmp_path / "dist"
+    sdist_dir.mkdir()
+    assert build_sdist(str(sdist_dir)) == "file-pkg-2.3.4.tar.gz"
+
+
+def test_build_sdist_version_scm(tmp_path, monkeypatch):
+    """Integration: build_sdist resolves dynamic version from setuptools_scm (git tag)."""
+    proj = tmp_path / "proj"
+    make_integration_project(proj, pkg_name="scm_pkg", pyproject_toml="""\
+[project]
+name = "scm-pkg"
+dynamic = ["version"]
+description = "Test"
+
+[build-system]
+requires = ["conan-py-build"]
+build-backend = "conan_py_build.build"
+
+[tool.conan-py-build.version]
+provider = "setuptools_scm"
+
+[tool.setuptools_scm]
+version_file = "src/scm_pkg/_version.py"
+""")
+    _git_init_and_tag(proj, "v3.0.0")
+    monkeypatch.chdir(proj)
+    monkeypatch.setenv("CONAN_HOME", str(tmp_path / "conan_home"))
+
+    sdist_dir = tmp_path / "dist"
+    sdist_dir.mkdir()
+    filename = build_sdist(str(sdist_dir))
+    assert filename == "scm-pkg-3.0.0.tar.gz"
+
+    with tarfile.open(sdist_dir / filename, "r:gz") as tar:
+        names = tar.getnames()
+        assert "scm-pkg-3.0.0/src/scm_pkg/_version.py" in names